Invalid CONTROL parameter

What causes this issue?

The activator was called with an invalid value for control parameter
CONTROL.

System Response

The activation process was cancelled.

How to fix this error?

Please use a valid value for parameter CONTROL. You will find this
value in the documentation for the activator. If the error occurs
during ABAP/4 Dictionary maintenance, please contact the ABAP/4
Dictionary hotline.

Error message extract from SAP system. Copyright SAP SE.